Doping Dependence of the Critical Current and Irreversibility Field in Y1-xCaxBa2Cu3O7-delta

TL;DR

This study investigates how doping levels affect the critical current and irreversibility field in YBa2Cu3O7-delta superconductors, revealing that overdoping enhances these properties.

Contribution

It provides experimental evidence that overdoping increases critical current and irreversibility field in YBa2Cu3O7-delta, expanding understanding of doping effects in high-temperature superconductors.

Findings

Critical current Jc is highest in overdoped samples.

Jc increases with hole concentration during annealing.

Irreversibility field increases with doping when scaled by reduced temperature.

Abstract

Critical current measurements were made on thin films of YBa2Cu3O7-delta and Y0.8Ca0.2Ba2Cu3O7-delta produced by sol-gel and pulsed laser deposition, respectively. Both samples have high critical currents at low temperatures and the critical current, Jc, is largest in the overdoped Y0.8Ca0.2Ba2Cu3O7-delta thin film. Annealing studies show a large increase in Jc with increasing hole concentration and suggests that the maximum Jc should occur for overdoped samples. The very overdoped region of the superconducting phase diagram was probed by studying bulk ceramic Y0.8Ca0.2Ba2Cu3O7-delta samples, where it was found that the irreversibility field systematically increases with increasing hole concentration when scaled by the reduced temperature (t = (1 - T/Tc)).